If you're very heavy, then your body is already under a lot of stress. It's really hard work for the heart to pump blood through a bmi 40 body.
This means that surgical and post surgical complications are far more dangerous for your body than it is for one that is more proportionate, weight and height wise. It also means that you are at a much higher risk of getting surgical and post surgical complications.
In short, it means that your body isn't going to handle surgery well, and even something like this could easily lead to your death.
That's why it's so important to loose weight for SRS.
And not just SRS, but for life.
There are little things you can do to loose weight. You need to do this carefully, because, as I said, your body is already very stressed.
Little things are like;
Switch to plain water instead of sodas/sweetened drinks.
Switch to dark chocolate (60% or darker) instead of other "treats". One little piece of dark chocolate has more flavor than a whole bar of milk chocolate.
Read the ingredients list of everything you buy and remember, it's organized by amount (this means, the first thing on the list is what there is most of in the container, the second is what is second most of in the container, and so forth..) so if sugar is one of the first 3-4 things, it's not "fit for consumption".
Make your own food and treats. (If you know exactly what you've put into the food then you automatically eat better.) Pre-fabricated and highly processed food can contain sickening amounts of sugar and salt.
And lastly,.. walk
You don't have to walk far, just as much as you're comfortable with.
You can always walk further tomorrow.
At 40 bmi, you will burn more energy in a ten minute slow walk than I (at bmi 27) will burn in a half hour brisk walk. Set your own pace.
If you want to have your surgery, and survive it, and "live" after it, it's up to you to change your life a little bit to make that possible.
I know it's tough, but the truth is, it's not about how you look, it's about your health, your life.
*offers a hug*